Top roll and method of covering same



ATENT OFFICE.

HOWARD STANLEY BRISTOL, OF NEWPORT, RHODE ISLAND.

TOP ROLL AND METHOD OF COVERING SAME.

No Drawing. Application filed. May 22,

My invention relates to the covering of top rolls as used in the textile industry and resides in a new and improved covering and the method of making the same and applying it to a top roll core. In the use of the words top roll, I include all varieties of rolls employed in the preparation of yarns and threads, such as drawing rolls, comber rolls, slubber rolls, twister rolls, spinning rolls, speeder rolls and the like, and in the use of the word core I contemplate all varieties of mechanical structures, including shells, ball hearing or anti-friction rolls, rolls of skeleton or spider construction as well as solid rolls, the lattertype being the most widely used.

According to my invention the roll covering is composed of soft rubber whlch has been left uncured or has been partly cured or vulcanized to a soft, or semi-soft state, but still remains in a more or less yielding and elastic condition. This covering may be variously compounded and brought to the above condition by any of the methods commonly known to the rubber industry, as the need requires, and after it is brought to that condition and either before or after it is applied to the core a secondary treatment is appliedto the rubber surface. This treatment has the effect of casehardening the entire surface, thus rendering it oil resistant at all exposed points, greatly increasing its durability and giving the surface several other qualities extremely necessary to the satisfactory operation of the roll in practice.

In modern yarn preparing machines, 1t is common practice to pass the sliver, or roving, between sets of rolls consisting of a cushion-like top roll mounted on and weighted onto a fluted steel bottom roll, the former being driven by the latter simply through contact. On ring spinning frames there are usually a plurality of these sets of top and bottom rolls, the first or back set revolving slowly and unwinding the roving from the bobbin on which it is wound. second set revolves faster and the front, or last set, revolves fastest of all. In this manner, the material passing through these sets of rolls is drawn out so that the individual fibers will be laid as parallel as possible. Now as it is necessary for uniform work that the fibers be at all times firmly gripped in the bite between the top and bottom rolls, without cutting or injuring the fibers, and

The

1925. Serial no. 32,213.

as the character of the surface of the top roll must be such that it is driven in a positive manner by contact with the bottom roll, it is common practice to cover the top rolls with a soft cushion-like or yielding material of some sort, such as cloth and leather, leather alone, cloth and parchment paper or similar materials. None of these materials are durable and leather, especially, is adversely affected by oil, and is expensive. All of these coverings soon become rough, make poor yarn and require frequent replacement.

Soft rubber, however, is an ideal material for use as a roll covering for the reason that it can be secured in a variety of flexibilities and densities and if it becomes rough, the surface ofthe rubber can be quickly renewed or redressed without replacing the whole covering. But it is common knowledge that soft rubber is adversely affected by oil especially the mineral oil used in considerable quantities for lubricating the rolls when in operation, the result being that the rubber is distorted and the surface is made sticky so that the yarn will not run well.

I am aware that numerous attempts have been made to overcome this objection, by constructing roll coverings with a soft in terior and a hard exterior surface by building up the covering with successive layers of uncured rubber differently compounded and vulcanizing the whole together with heat. This method is extremely expensive however, and the products" made in this way have not met with much favor for the reason that when coverings are made in this way it has not been found possible to construct a covering having a finished surface possessing all the necessary and essential qualities for satisfactory operation, such as flexibility, resistance to oil, proper traction on the bottom roll, non-licking up of fibers etc. Either the outer layer is so thick and hard that the cushion-like qualities of the covering are greatly diminished and the surface loses its flexibility as well as its grip of the bottom roll, or if made with a softer surface the same is attacked by the oil and while the grip on the fluted bottom roll as well as the cushion is improved, the surface becomes sticky very quickly and works poorly. Rubber coverings constructed in this manner invariably have exposed ends or other exposed spots on the soft rubber layers which are attacked by the oil, thus distorting the covering and impairing'its durability. FOl'lihGSB reasons soft rubber coverings have found only very restricted use more especially on cores of large diameter where there is little opportunity for the oil to come in contact with the covering.

I have discovered that it is possible by my method to economically make a covering out of soft rubber which overcomes all of these objections and which not only has all outer or exposed surfaces thoroughly oil resistant, but also a covering which has greatly increased durability and is free from tendency to lick up fibers while still possessing suliicient surface flexibility and traction on the bottom fluted roll. This I do by means of a secondary vulcanization or casehardening process which I apply to the entire exposed surface of the soft rubber covermg either before or after it is applied to the core. In effect, my invention provides a soft rubber covering which has been given a very thin but comparatively hard oil resistant surface without destroying the essential unity of the covering as a whole or diminishing any of its desirable properties. Thus my roll covering will be seen to be an entirely new product and very different from any other covering previously known or employed by the textile art.

While my discovery permits me to harden the surface of any kind of a soft rubber covering after it is applied to the core either by moulding, vulcanizing, cementing, or any other means, it also permits me to manufacture in a large and economical way these casehardeningcoverings in tube form without seam, ground and turned accurately to size, and these tubes I can then press onto the core with or without the use of cement or glue. In carrying out my invention with the use of tubes, the proper sizes and qualities of tubes having been selected, my next step is to caseharden the tubes, the idea being to simply harden the whole outer surface so as to render it oil resistant and still retain cushion properties, fiexibility, traction and freedom from fiberlick. In practice I prefer to employ the cold cure process, using sul phur chloride in a solution of carbon tetrachloride, and I have securec good results by dipping the tubes quickly in a mixture of equal parts by weight of these two liquids.

Now while I have found that the half and half mixture described above does very well under certain circumstances I have also found that I can effect varying results in durability and running properties by varying the casehardening treatment somewhat. For example, by using fewer parts of sulphur chloride and more parts of carbon tetrachloride instead of the half and half mixture referred to above and by varying the duration of the dip, I can secure a more flexible outer surface on the rubber covering which has a better grip on the bottom roll and yet has suliicient durability and oil resistance. This is important, as different mills require different qualities of covering. I also find that it is at times of great advantage to be able to renew or change the nature of the casehardened surface, and this I can do by largely or entirely removingthe thin hardened surface and subjecting the freshly exposed surface of soft rubber'to the special casehardening treatment re quired without the necessity of replacing the entire covering. I am not limited to the dipping process for applying the sulphur chloride solution as I may apply it with a brush, cloth, swab, special machinery, or any convenient method.

Nor am I limited to the use of sulphur chloride in solution as a casehardening agent, or to any special temperature, or any special solvent. I may use carbon disulphide, benzene, naptha, or any other solvent, and I may use sulphur chloride in vapor form instead of solution. I may also sub stitute sulphur bromide or sulphur iodide, or a sulphur compound of any of the halo gens, or I may use alternate treatments of hydrogen sulphide and sulphur dioxide, or still further I may use hypochlorous acid. Further variations and desirable manipulations may be discovered by those skilled in the art, the essence of my invention being the casehardening of the entire exposed surface of a rubber covering for a textile top roll without altering the interior in any way so as to deleteriously affect its desirable properties, said casehardened surface being an integral part of the finished covering constituting my invention.

By the term soft rubber as used in this application, I wish to be understood as including all of the various raw products included under the trade name ofcrude rubber and rubber substitutes from whatever source or locality secured. I also include variously compounded mixtures of any of these with other materials or with each other, either in the form of plastic dough or partly cured by any of the well known curing processes commonly known to the rubber industry by which the uncured product is converted from a practically unelastic material to a more or less elastic and resilient article in contradistinction to the fully cured rubber which is hard and vitreous and commonly called hard rubber. I wish to also include under the term soft rubber the above uncured or partly cured products in combination with cloth, which products are commonly known in the trade as cloth faced or cloth inserted rubber. 7

My invention also contemplates the treatment of the surface of the soft rubber with a mixture preferably containing pyroxylin, which mixture upon drying forms an oil Sit) resistant coating. A rubber covered roll treated in this manner possesses many desirable properties, and the durability and running qualities of the coating may be varied by treating the surface of the coating chemically, as for example, with sulphur clllOIldB or a similar agent, the result then being to alter the surface of the coating to reduce its stickiness, in some instances, or to increasethe grip on the fluted bot om roll in other instances, at the same time retaining the requisite durability.

I claim,

1. The improvement in the making of top rolls for textile machines which consists in covering a core with soft rubber, and treating the entire exposed surface of said rubber covering with sulphur chloride.

2. As a new article of manufacture, a top roll for textile machines comprising a core covered by soft rubber and the entire surface of said rubber treated with sulphur chloride.

3. As a new article of manufacture, a covering for top rolls and the like comprising a cylindrical body of soft rubber, the entire surface of which has been treated with sulphur chloride.

at. The improvement in the making of top rolls for textile machines which consists in covering a core with a soft rubber tube applied in tube form and changing with a chemical reagent the rubber coi'nprising the exposed surface of said rubber tube so as to form a comparatively thin, hard, flexible and oil resistant rubber surface thereon completely encasing said soft rubber tube.

5. As a new article of manufacture a top roll for textile machines comprising a core covered with a soft rubber tube applied in tube form, said rubber tube having a thin,

hard, flexible and oil resistant rubber surface thereon completely encasing said rubber tube, said surface being formed by applying sulphur chloride in carbon tetrachloride to said tube. V

6. The improvement in the making of top rolls for textile machines which consists in covering a cylindrical body with partly cured rubber and by means of a secondary vulcanization with a chemical reagent changing the rubber comprising the surface of said cylindrical body covering of partly cured rubber so as to form a comparatively thin, hard, flexible and oil resistant rubber surface thereon.

7. As a new article of manufacture, a top roll for textile machines, comprising a core having a cylindrical soft rubber covering, said soft rubber having as an integral part thereof a comparatively thin, hard, flexible and oil resistant rubber surface encasing the cylindrical drawing surface and ends of said soft rubber covering.

8. As a new article of manufacture, a top roll for textile machines, comprising a core covered with a soft rubber tube applied in tube form, said rubber tube having as an integral part thereof a comparatively thin, hard, flexible and oil resistant rubber surface encasing said soft rubber and eliminating all exposed surfaces thereof.

9. As a new article of manufacture, a covering for top rolls for textile machines comprising a soft rubber tube having as an integral part thereof a comparatively thin,

hard, flexible and oil resistant rubber surface encasing the cylindrical drawing surface and ends of said tube when same is applled to a core.

HOWARD STANLEY BRISTOL. 

